<template>
  <div class="home-page">

    <div class="banner">
      <div class="container">
        <h1 class="logo-font">conduit</h1>
        <p>A place to share your knowledge.</p>
      </div>
    </div>

    <div class="container page">
      <div class="row">

        <div class="col-md-9">
          <div class="feed-toggle">
            <ul class="nav nav-pills outline-active">
              <li class="nav-item" v-if="user">
                <nuxt-link 
                  class="nav-link" 
                  :class="{active: tab === 'your_feed'}"
                  exact
                  :to="{
                    name: 'home',
                    query: {
                      tab: 'your_feed'
                    }
                  }">Your Feed</nuxt-link>
              </li>
              <li class="nav-item">
                <nuxt-link 
                  class="nav-link" 
                  :class="{active: tab === 'global_feed'}"
                  exact
                  :to="{
                    name: 'home'
                  }">Global Feed</nuxt-link>
              </li>
              <li class="nav-item" v-if="tag">
                <nuxt-link 
                  class="nav-link" 
                  :class="{active: tab === 'tag'}"
                  exact
                  :to="{
                    name: 'home',
                    query: {
                      tab: 'tag',
                      tag: tag
                    }
                }"># {{ tag }}</nuxt-link>
              </li>
            </ul>
          </div>
          <div 
            v-for="article in articles"
            :key="article.slug"
            class="article-preview">
            <div class="article-meta">
              <nuxt-link :to="{
                name: 'profile',
                params: {
                  username: article.author.username,
                  slug: article.slug
                }
              }">
                <img :src="article.author.image" />
              </nuxt-link>
              <div class="info">
                <nuxt-link :to="{
                  name: 'profile',
                  params: {
                    username: article.author.username,
                    slug: article.slug
                  }
                }">
                  {{ article.author.username }}
                </nuxt-link>
                <span class="date">{{ article.createdAt | date('MMM DD,YYYY') }}</span>
              </div>
              <button 
                class="btn btn-outline-primary btn-sm pull-xs-right" 
                :class="{active: article.favorited}"
                @click="onFavorite(article)"
                :disabled="article.favoriteDisabled"
              >
                <i class="ion-heart"></i> {{ article.favoritesCount }}
              </button>
            </div>
            <nuxt-link class="preview-link" :to="{
              name: 'article',
              params: {
                slug: article.slug
              }
            }">
              <h1>{{ article.title }}</h1>
              <p>{{ article.description }}</p>
              <span>Read more...</span>
            </nuxt-link>
          </div>
          <!-- 分页 -->
          <nav>
            <ul class="pagination">

              <li class="page-item" :class="{active: item === page}" v-for="item in totalPage" :key="item">
                <nuxt-link class="page-link" :to="{
                  name: 'home',
                  query: {
                    page: item,
                    tag: tag,
                    tab: tab
                  }
                }">{{ item }}</nuxt-link>
              </li>

            </ul>
          </nav>
          <!-- /分页 -->
        </div>
        <div class="col-md-3">
          <div class="sidebar">
            <p>Popular Tags</p>
            <div class="tag-list">
              <nuxt-link 
                :to="{
                  name: 'home',
                  query: {
                    tag: item
                  }
                }"
                class="tag-pill tag-default" 
                v-for="item in tags" 
                :key="item">{{ item }}</nuxt-link>
            </div>
          </div>
        </div>
      </div>
    </div>

  </div>
</template>

<script>
  import { 
    getArticles,
    getYourFeedArticles,
    addFavorite,
    deleteFavorite 
  } from '@/api/article'
  import { getTags } from '@/api/tag'
  import { mapState } from 'vuex'
  export default {
    name: 'HomeIndex',
    async asyncData ({ query }) {
      const page = parseInt(query.page || 1)
      const limit = 20
      const tab = query.tab || 'global_feed'
      const tag = query.tag
      const loadArticles = tab === 'global_feed'
        ? getArticles
        : getYourFeedArticles 
      const [ articleRes, tagRes ] = await Promise.all([
        loadArticles({
          limit: limit,
          offset: (page - 1) * limit,
          tag
        }),
        getTags()
      ])
      const { articles, articlesCount } = articleRes.data
      const { tags } = tagRes.data

      articles.forEach(article => article.favoriteDisabled = false)

      return {
        articles,
        articlesCount,
        limit,
        page,
        tags,
        tab,
        tag
      }
    },
    watchQuery: ['page', 'tag', 'tab'],
    computed: {
      ...mapState(['user']),
      totalPage () {
        return Math.ceil(this.articlesCount / this.limit)
      }
    },
    methods: {
      async onFavorite (article) {
        article.favoriteDisabled = true
        if (article.favorited) {
          await deleteFavorite(article.slug)
          article.favorited = false
          article.favoritesCount -= 1
        } else {
          await addFavorite(article.slug)
          article.favorited = true
          article.favoritesCount += 1
        }
        article.favoriteDisabled = false
      }
    }
  }
</script>

<style lang="scss" scoped>

</style>